Help with APN on T-Mobile

Hi, just couldn't find how to do it. I've got a lg g2 d-801 T-Mobile, which is unlocked and I can use it where I am (Romania). The problem is with the internet connection. I can't select a new apn, the only option I have is the stock apn with which the phone came. Other than that no other options. What should I do? I already rooted the phone, perhaps I should flash an international rom or is there something I can do without needing to flash roms or a new recovery? Thx

XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality.Are you a developer?